1. Field of the Invention
The present invention relates to a vibration damper material which exhibits vibration damping properties when it is used.
2. Description of the Background Art
Vibration damper materials comprised vibration damping layers utilizing viscoelastic materials are known as materials which can suppress vibrations and noise. Such vibration damper materials are utilized by being adhered or stuck onto an adherend to provide vibration damping effect of the adherend. For example, they are placed on the floors of automobiles and around such areas to prevent vibrations and noise from being transmitted inside the vehicle.
One of such vibration damper materials is a sheet in which a pressure sensitive adhesive layer is bonded to a vibration damping layer consisting of an asphalt sheet or a vulcanized rubber sheet. However, such vibration damping sheets have problems in that the asphalt sheet and the vulcanized rubber sheet have a high modulus of bending elasticity. As a result, they have an impaired ability to follow curved surfaces and impaired adhesive reliability when they are applied to curved areas. Therefore, there is a risk that the pressure sensitive adhesive layer will peel when, for example, the temperature changes or they suffer vibrations or impacts. As a result, gaps are formed between the adherend and the pressure sensitive adhesive layer, thus leading to loss of the vibration damping ability.
In order to prevent such peeling from occurring there is a one method whereby the asphalt sheet is adhered to the adherend using an adhesive. However, this method has two main disadvantages. First, that it takes time to coat and dry the adhesive and the operating efficiency is poor.
There is also another method in which the vibration damping sheet is formed in advance with a shape which is similar to the curved surface of the adherend. However, this method is impractical since it is not very widely applicable and there will be cases where the shape of the adherend cannot be specified at the time that the vibration damper material is produced.